It's a metaphorical term of art, but also a sentiment among companies. They do treat talent as property, surprisingly often.
And there's often a fair bit of tit-for-tat and specific arrangements about poaching and when it's okay. Which is understandable in such a small, chummy industry (think Silicon Valley venture-backed startups, which are all about networking).
But it's also illegal, and devalues programmers, both monetarily and metaphorically.
Yeah, it's a metaphor that analogizes people and property.
I wouldn't have any qualms about working with, say, purchasing managers who talked about "poaching" component orders from one another, because they'd be talking about property as property.
I think you're really stretching here. The core issue is whether companies value their employees--that comes through in how the employees actually get treated, not the use of one word vs. another.
From the company's point of view, they've invested in finding you, and getting you up to speed, and now they have to start over. Even if they get someone equally talented at the same pay, the company has lost that initial recruiting cost and investment. So from their point of view, that's what is being "poached."
That is not counting the time it will cost to do these things.
If a company wants to avoid that situation, they have plenty of options available. They could offer employees long-term contracts, so the stability goes both ways. They could try to be more proactive in fixing the problems that make people want to leave. They could pull a Google and try to make their work environment so good that it's almost impossible to replicate.
For the most part, companies don't do these things, and then get surprised when employees leave. They want to have their cake and eat it too, and are upset to discover that the labor market works both ways.
I learned at a previous employer that HR's "how big should our raises be this year" numbers were influenced by year over year turnover trends. If too many people quit, raises went up the next year.
That's a cost of doing business. Any employment relationship is a week to week exchange of services for money. Employees and employers do generally invest their reputations and goodwill in the relationships, but the ultimate distillation of employment is my money for your time.
The fact that some employers have more costly onboarding processes than others is a competitive disadvantage, not a rationale for demand-side collusion in the job market.
I prefer to think of "poaching" in more appropriate terms -- supply and demand. Limited supply, demand increasing, and the market bears what it will.
Anyone who complains about this environment needs to consider another line of work.